Brass predicament…

[Bater]

Going from .264” to .243” is so small it wouldn’t make a difference even in a minimum no-turn neck chamber. Have you run a piece of 260 brass through your 243 dies and measured the neck thickness? You couldn’t ask for a better case, other than the head stamp won’t say 243.

Yeah that probably is the best way to do it. And if I go with 260 I have Alpha and Peterson that make SRP. My only concern was potentially having to turn necks, but it’s good to hear that you don’t think that would be an issue.

 

[pods8 (Rugged Stitching)]

Yeah I think you’re right. It’s amazing what kind of pressure you can run with SRP. With my 6GT and 260AI using SRP I had to start looking for other less obvious signs than the standard primer criteria that we are used to.

Which as long as folks are honest with themselves about it I have no problem, not like I don't run things hot at times, I just don't like that the realities of the SAW are kinda swept under the rug.

Also one potential perk on the 260 brass is if your chamber isn't a tight fit on regular 243 brass (like it should be) then starting with 260brass would easily let you create a false shoulder off the get go (vs necking up 243 first before necking it back down).

 

[pods8 (Rugged Stitching)]

Yeah that probably is the best way to do it. And if I go with 260 I have Alpha and Peterson that make SRP. My only concern was potentially having to turn necks, but it’s good to hear that you don’t think that would be an issue.

Assuming you have a 243 die already just neck down a piece of that brass, seat a bullet and measure the neck to answer your question of what size it would be. The smith can tell you what the reamer is.

 

[TaperPin]

Yeah that probably is the best way to do it. And if I go with 260 I have Alpha and Peterson that make SRP. My only concern was potentially having to turn necks, but it’s good to hear that you don’t think that would be an issue.

Difference in circumference between 260 and 243 is .829 - .763. = .066” Which is roughly 8%.

If your 260 brass has .015” thick neck brass it would grow by about 8% to .0162”

Lapua brass is often .015”, Winchester .014” and federal .016”. Anyone know what Peterson or other brands are?

 

[TaperPin]

Assuming you have a 243 die already just neck down a piece of that brass, seat a bullet and measure the neck to answer your question of what size it would be. The smith can tell you what the reamer is.

That’s good advice - custom reamers vary all over the board.

 

[Bater]

Difference in circumference between 260 and 243 is .829 - .763. = .066” Which is roughly 8%.

If your 260 brass has .015” thick neck brass it would grow by about 8% to .0162”

Lapua brass is often .015”, Winchester .014” and federal .016”. Anyone know what Peterson or other brands are?

I just measured the Peterson LRP at .0145”

 

[PathFinder]

I'm using Alpha LRP 260 brass in my 243 Improved. Necks are a little thick, but still have .004 clearance. Loaded necks are .274-.275 OD, neck of my chamber is .279.
I went pretty far up in charge (51 grains) of H1000 with a 115 DTAC at 3085 fps in a 20" barrel. That load was definitely hot, but only showed a faint ejector mark. Primer pockets didn't show any growth in one firing. The final load is 47.7 at 2900 fps.
Either Alpha or Lapua LRP should be more than adequate for many firings.

Sent from my Pixel 6 using Tapatalk

 

[pods8 (Rugged Stitching)]

Loaded necks are .274-.275 OD,

My plinking 243 brass (dogtown, bough a bunch back in the day on sale) is this size so sounds like the alpha necked down isn't any larger.